1. Field of the Invention
The present invention relates to an electromechanical actuator that has a screw mechanism, converts rotational driving force which is output by an electric motor into linear driving force, and outputs the converted driving force.
2. Description of the Related Art
Conventionally, an electromechanical actuator having an electric motor and a screw mechanism has been used in various fields such as the field of aircrafts. This electromechanical actuator converts rotational driving force that is output by the electric motor into linear driving force and outputs the converted driving force, using the screw mechanism. The electromechanical actuator drives various kinds of equipment by an output portion being displaced so as to extend and retract in a linear direction with respect to a housing. Note that the aforementioned electromechanical actuator has an advantage of a smaller maintenance burden than that of a hydraulic actuator that operates by pressure oil being supplied thereto.
With the aforementioned electromechanical actuator, a jammed state may occur in the screw mechanism due to causes such as prying or seizure. If a jammed state occurs in the electromechanical actuator, it becomes difficult to move the output portion back and forth with respect to the housing.
U.S. Pat. No. 5,214,972 discloses an electromechanical actuator provided with a first actuator and a second actuator. The first actuator and the second actuator are installed so as to coaxially extend in opposite directions. The first actuator and the second actuator each include an electric motor and a ball screw mechanism. In the electromechanical actuator having this configuration, even if a jammed state occurs in the screw mechanism in one of the first and second actuators, the other of the first and second actuators is in an operable state. For this reason, in this electromechanical actuator, even if the aforementioned jammed state occurs, the output portion can be withdrawn to a position at which the output portion is retracted with respect to the housing.